when i foolishly ordered my heads thru ICH i asked them to be machined for 1.625 spring cups, "you don't need them" was their answer," you can do everything with a 1.550 spring". ok i'll go with that so i asked them to be machined for 1.550 cups, "you don't need them, spring locators are much better", well they were wrong & i experianced exactly what you posted. first time the heads came off i had them machined for cups & lowered the cup seat position 0.040 so i could go for 2" installed if i needed. those spring locator shims were shyte.